Circuit control device



1938. c. J. WERNER CIRCUIT CONTROL DEVICE Original Filed Sept. 6, 1934 INVENTOR Call/1 J h/erner ATTORNEYS Patented Nov. 1, 1938 UNITED STATES CIRCUIT CONTROL DEVICE Calvin J. Werner, Dayton, Ohio, assignor to General Motors Corporation, Detroit,\ltiich., a corporation of Delaware Original application September 6, 1934, Serial No. 742,941, now Patent 2,095,579, dated October 12, 1937. Divided and this application September 5, 1935, Serial No. 39,293. Renewed March 7, 1938 10 Claims.

This invention relates to circuit control devices and more particularly to circuit control devices that are responsive to a thermal-responsive element.

This application is a division of my copending application, Serial No. 742,941, filed September 6, 1934, which became Patent No. 2,095,579 October 12, 1937.

An object of this invention is to provide a thermal-responsive circuit control device that is inexpensive to build, durable and efficient, and quiet in operation.

Another object of this invention is to provide a circuit control device having more than one set of contacts controlled by a single controlling ele ment, so that a plurality of electrical circuits are controlled in a predetermined sequence in re sponse to said element.

Another object of this invention is to provide a circuit control device that is adapted to control the starting and running circuits of an electric motor, as well as providing overload protec tion for the motor, said circuit control device being so constructed and arranged that it is responsive to current flow through a thermal responsive element, and not appreciably affected in operation by changes of ambient temperature.

Another object of this invention is to provide a circuit control device for controlling an electrical circuit, which circuit control device is actuated by a thermal-responsive element responsive to current flow through said element, and has means for effecting a substantially snap make" and-break of the contacts.

From the disclosed embodiment of this invention, it will be apparent that in one aspect of the invention these objects are accomplished by a circuit control device comprising, in combination, a main support, an auxiliary support member movably pivotally mounted to the main support, resilient means biasing the auxiliary sup port in one direction, a plurality of movable contacts pivotally mounted to the auiiiliary support member and movable therewith and relative thereto, said movable contacts being disposed at diirerent angles with respect to the auxiliary support member, cooperating stationary contacts in alignment for engagement with each of the movable contacts, which stationary contacts arrest movement of the movable contacts in one direction and are adjustably mounted with respect to the movable contacts, stop means secured to the stationary contacts and adjustable therewith for arresting movement of the movable contacts in the other direction, a thermal-responsive element having one end anchored to the auxiliary support member and the. other end adjustably secured to the main support for controlling the movement of the auxiliary support member, and resilient means for efiecting snap engagement and disengagement of the contacts in response to said movement of the auxiliary support member.

Further objects and advantages of the present invention will be apparent from the following de scription, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

Figures 1, 2 and 3 are side, front, and opposite side views respectively of a preferred form of circuit control device embodying the present invention.

Figures 1, 5 and 6 are sectional front views of the circuit control device shown in Figures 1, 2 and 3, and show different operating positions of the circuit control device.

Figures 7 and 8 are enlarged fragmentary views of a portion of the circuit control device shown in the previously mentioned figures, and show different stages of the operation of the circuit control device illustrated.

Figure 9 is a fragmentary back view of a circuit control device embodying a preferred form of the present invention.

With particular reference to Figures 1 to 6 inelusive, a main support it comprises a front portion it, a side portion it and a back it, which front portion, side portion and back are preferably integrally formed. The front portion 52 preferably has ears l8 punched therefrom, and integral therewith, for securing the circuit control device to a suitable housing or support, not shown. Ears 2d are preferably provided at one end of the front portion l2 and at the same end of the back portion 5 6, which ears extend through suitable openings in a plate 22 and are bent or twisted to secure the plate 22 to the end of the support 50.

A movable auxiliary support member 24 that is preferably substantially U-shaped, having side portions 25 and 28 and a connecting portion 38, is pivotally mounted intermediate the front portion l2 and the back portion it of the support on a pivot shaft 32. The pivot shaft 32 extends through openings such as 34 in the side portions 26 and 28, and is insulated therefrom by insulating collars 36. Shoulder portions, such as 38, on the insulating collars 36, insulatingly space the auxiliary support member 24 from the main support ill. A spring 40 has one end anchored to a connecting portion 52 of the auxiliary support member 24 by a hook portion 44 that passes through a hole 46 in the connecting portion 32; and has its other end anchored to a plate 48 by a hook portion 50 that passes through a hole 52 in the plate 48. The plate 48 is secured to the main support ID by lugs such as 54 that extend through suitable slots in the plate 48 and are bent or twisted to clamp the plate in place. The

lugs 54 are preferably integral with the front I2 and the back I6 of the main support. The plate 48 is preferably made of insulating material. The spring 40, being a tension spring, biases or urges the auxiliary support member in one dircction about the pivot shaft 32.

A thermal-responsive element 56, that preferably comprises a wire having a relatively high temperature coefiicient of expansion, has one end connected to a lug 58 on the auxiliary support member 24, that is preferably located near the end of that member and on the opposite side of the pivot shaft 32 from the spring 40. The end of the thermal-responsive element 56 passes through an opening 60 in the lug 58, and is pref: erably secured thereto by twisting, as at 62. The other end of the thermal-responsive element extends through an opening 64 in an externally threaded member 66, and is preferably bent, as at 68, to anchor the end thereof and prevent the member 68 from slipping off of the wire. The main support I0 and thermal-responsive element 56 preferably have substantially the same temperature coefficient of expansion within reasonable limits, so that changes of temperature of the entire switch will not effect operation thereof or appreciably affect the operation. This prevents appreciable change in the operating characteristics of the switch due to changes of ambient temperature. The externally threaded member 66 is mounted in an aperture I0 in the plate 22, and is provided with a cooperating nut I2, threaded thereon, to provide an adjustable anchor for the end of the thermal-responsive element so that the effective length of the thermal-responsive element is adjustable.

Insulating stationary contact support members I4 and I6 are secured to the back I6 of the main support I0 by screws I8 and respectively, which screws are preferably provided with washers 82 and 84 respectively, intermediate the screw heads and the back I8. As best shown in Figure 9, the screws 78 and 80 preferably extend through elongated openings 86 and 80 respectively, in the back I6, so that the stationary contact support members I4 and I6 are adjustable laterally as viewed in the figure. Stationary contacts and 92 are secured to portions 94 and 96 of the contact support members I4 and I6 respectively, so that they are insulated from the back I6, and screws 98 and I00 are threaded into the contacts I4 and I6 respectively, to provide means for making electrical connections to the contact. Insulating stock portions I02 and I04 are preferably integral parts of the contact support members I4 and I6 respectively, and are spaced from the contacts 50 and 92 respectively.

Substantially V-shaped notches I06 and I08 are provided in the ends of the side portions 26 and 28 of the auxiliary support member 24, which notches provide pivotal supports for movable contacts H0 and H2 respectively, having substantially knife edges, such as H4, that rest in the notches. Contact points H6 and H8 are secured to the movable contacts H0 and H2 respectively, in alignment for engagement with the stationary contacts 00 and 92 respectively. Springs I20 and I22 have their ends disposed in notches I32 and I34 in the movable contact members H0 and H2 respectively, and their respective ends have hook portions I24 and I26 that are anchored in holes I28 and I30 in the movable contact members H0 and H2 respectively. The other ends of the springs I20 and I 22 have hook portions I36 and I38 respectively, that extend through holes I40 and I42 in lugs I44 and I46, respectively, which lugs are preferably inte gral with the side portion 20 of the auxiliary support member, so that the springs are anchored thereto.

In Figures 7, 8 and 9, the reference numerals similar to those previously used refer to similar parts that perform similar functions.

In the preferred form of the circuit control device shown in Figures 1 to 9 inclusive, the auxiliary support member 24 and the stationary contact-carrying members 14 and I6, as well as the notches I06 and I08, are so disposed that the angular relations of the contacts H0 and H2 to the auxiliary support member 24 and the action lines of the springs I20 and I22 differ when the contacts H0 and H2 are in their normal engaged or disengaged positions. This difference in angular relations effects operation of the contacts H0 and H2 at different times in response to the movement of the auxiliary support member 24 about the pivot shaft 32. The springs I20 and I22 urge the contacts H0 and H2 respectively, into engagement with their respective notches I06 and I08 and also are so disposed that the center lines of action of these springs cross the pivotal axes of the contact to effect engagement and disengagement of the contacts with a snap action. In the particular form shown, the angular relation of the movable contact H2 to the auxiliary support member 24 and the action line of the spring I22 is such that the action line of the spring I22 crosses the pivotal axis of the contact I I 2 before the action line of the spring I20 crosses the pivotal axis of the contact H0. Hence, in this form, it takes a lesser movement of the auxiliary support member 24 to effect actuation of the contact H2 than it does to effect actuation of the contact H0. When the contacts H0 and H2 move toward the stationary contacts 90 and 92 respectively, the stationary contacts arrest the motion of the movable contacts in that direction. When the movable contacts move in the opposite direction, the motion thereof is arrested by the stop portions I02 and I04.

The spring 40 biases the auxiliary support member 24 in a counterclockwise direction, as viewed in Figures 4 to 6 inclusive. When the auxiliary support member moves in that direction under the influence of the spring 40, disengagement of the contacts 92 and H8 is first effected, and then the contacts 90 and H6 are disengaged. However, the position and motion of the auxiliary support member 24 are controlled by the thermalresponsive element 56. The effective length of that element is preferably so adjusted that the contacts are normally engaged, so that when the thermal-responsive element expands due to a change of the temperature thereof the force of the spring 40 moves the support member 24 to effect disengagement of one or both sets of contacts, depending upon the degree of expansion of the thermal-responsive element 56. Upon return of the temperature of the thermal-responsive element to normal, the contraction of the element actuates the auxiliary support member 24 in the opposite direction to effect engagement of the contacts.

As best shown in Figures 7 and 8, it is important to note that since the pivotal axes of the contacts H0 and H2 are moved, the substantially spherical surface of the movable contacts rolls on the surface of the stationary contacts before disengagement of the contacts is effected. Although the force utilized to actuate the corn areas?! tacts is relatively small, a very large force is eil'ected to break any welds that might occur and that would tend to hold the contacts or cause them to stick. The reason tor the large force that is eflected by the contacts for breaking such welds is, of course, the leverage or mechanical advantage that is beneficially utilized.

From the aforegoing description of the construction and mode of operation of the present switch it is apparent that the switch comprises a support III carrying stationary contact stops and 92, an auxiliary support or plate 28 pivoted at a point 32 remote from the stationary contact stops 90 and 92. The switch has contact arm members I! and H2 carrying respectively contacts H6 and H8 which are engageabie with the contact stops 90 and 92 respectively. Spring members I20 and I22 are connected respectively with the contact arm members H0 and III near their contacts. Each contact arm member and its companion spring member are hingedly connected with the plate 28 at spaced points, one point being substantially nearer to the plate pivot 32 than the other. For example, the contact arm Ho and its companion spring member I20 are hingedly connected with the plate 2! at spaced points with the fulcrum IN and the spring eye I, respectively, the latter being substantiaily nearer to the plate pivot 32 than the former. The action line of force of each spring member makes a relatively small acute angle with the companion arm member and this action line force lies normally on the side or the arm on which its companion stationary con tact stop is located. For example, the action line of lflil makes a relatively small acute the contact arm member ll and tllls 1' n line lies normally on the side of a member lie on which its companion stationary contact stop ls located. As shown Figs. 4 and '3, the action line of spring we is on the left side of the contact arm member M9 also the left side oi the fulcrum l Ml of the contact arm The angle between one of arm one contact spring members is less the angle leetvveen the other pair of arm and spa members. angle between the action llne oi spring 1122 contact M2 is less than the angle between the action line of spring sec and con tact Mil.

The switch has means for moving ancillary support or plate 28 which includes the coil spring ill for moving the plate in one direction and the Wire for moving the plate in the other ell rectlon. As the plate begins to move counter-- clockwise as shown in Fig. 4, as the wire 5t? expanels, the contact points H6 and Hit remain in engagement with the contact stops to and until the bias effected by the springs llll and i222 is reversed. As the plate Bil moves counterclockwise the action line of spring l shifted from the left-hand side of contact arm ill. and its pivotal connection with the plate 28 toward the right-hand side thereof, whereupon contact H8 is separated from contact stop 92 and moves against contact stop I04. Further movement of plate 28 in a counter-clockwise direction causes the action line of spring IZI) to be shifted from the lefthand side of contact arm till and its pivotal connection with the plate 28 to the righthand side thereof, whereupon the contact H5 is separated from contact stop 90 and engages the stop I02. Thus the reversal of bias takes place first with respect to that pair of spring and contact arm members which normally make the smallest acute angle with each other.

The contact stops I02 and I operate to limit movement of the contact arms H0 and I I2 away from the first mentioned contact stops 80 and 92 when the bias of the springs I20 and I22 is reversed. These stops I02 and I are so located that a similar relation between the contact arms and their respective cooperating springs will exist when the contact arms are engaged with these last mentioned stops I02 and I as existed when these contact arms engage the first mentioned stops 9|! and 92. This is done in order that the contact arm I I2 which separates itself first from its contact 92 during counterclockwise relation of plate 24, will likewise. separate itself grst from its contact stop lIil during clockwise rotation of the plate 28, which is due to contraction of the wire 56. It is obviously within the scope of the present invention to locate the stops I02 and I so that both contact arms H0 and H2 will be restored to normal condition simultaneously, or contact arm H0 ahead of contact arm II2 if desired. However, for the control of the starting and running circuits of an electric motor it is desirable to have the contact iI2 return to its contact 92 at least by the time contact arm IIIi has returned into engagement with contact 90. In order to assure this,

the present switch is constructed so that contact I I2 will reengage contact 92 ahead of the engagemerit of contact arm III! with contact Bil.

Some of the advantages of this circuit control device are as follows:

1. It is relatively easy and inexpensive to solid.

tlon responsive to the control of the thermal- .responslve element.

6. It is easily adapted to different uses and applications by changes of a very few parts.

7. it is efilclent, because of the direct heating feature of a thermal element that does not reoolre much energy for operation.

While the embodiment of the present inventlon as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all ccmlng within the scope of the claims which follow.

What is claimed is as follows:

i. A swltch comprising, in combination, a main support, an auxiliary support member electrically insulated from and pivotally connected to the main support, means resiliently urging the auxiliary support member in one direction about its pivotal connection to the main support, a movable contact electrically and pivotally connected to the auxiliary support member, a cooperating station any contact insulatingly secured to the main support in alignment for engagement with the movable contact, means effecting snap engagement and disengagement of the contacts in response to movement of the auxiliary support member, and a thermal-responsive element for controlling the movement of the auxiliary support member, said thermal-responsive element comprising a substantially straight wire adjustably anchored at one end to the main support and having its other end electrically and mechanically connected to the auxiliary support member, said wire having a temperature coefilcient of expansion sufficiently similar to that of the main support that change of temperature within reasonable limits of the entire switch will not be detrimental to the control of the contacts by the thermal-responsive element.

2. A switch comprising, in combination, a main support, an auxiliary support member movably pivotally mounted to the main support, resilient means biasing the auxiliary support in one direction, a plurality of movable contacts pivotally mounted to the auxiliary support member and movable therewith and relative thereto, said movable contacts being disposed at different angles with respect to the auxiliary support member, cooperating stationary contacts in alignment for engagement with each of the movable contacts, which stationary contacts arrest movement of the movable contacts in one direction and are adjustably mounted with respect to the movable contacts, stop means secured to the stationary contacts and adjustable therewith for arresting movement of the movable contacts in the other direction, a thermal-responsive element having one end anchored to the auxiliary support member and the other end adjustably secured to the main support for controlling the movement of' the auxiliary support member, and resilient means for effecting snap engagement and disengagement of the contacts in response to said movement of the auxiliary support member.

3. A switch comprising, in combination, a main support, an auxiliary support member, pivot means movably connecting the auxiliary support member to the main support, means resiliently urging the auxiliary support member in one direction about the pivot means, a movable contact pivotally connected to the auxiliary support, a cooperating stationary contact in alignment for engagement with the movable contact, means effecting snap engagement and disengagement of the contacts in response to movement of the auxiliary support member, and a thermal-responsive electrical resistance element anchored to the main support and to the auxiliary support member for controlling the movement of the auxiliary support member, the length of the thermal-responsive element being practically equal to the distance between the place of anchoring the thermal-responsive element to the main support and the pivot means and said main support member and thermal-responsive element having substantially similar temperature coefficients of expansion so that the operation of the switch is not appreciably aifected by changes of ambient temperature.

4. An electric switch comprising a support carrying two stationary contact stops, a plate pivoted upon the support at a point remote from the stationary contact stops, contact arm members each carrying a contact engageable with a stationary contact stop, spring members each connected with a contact arm member near its contact, each contact arm member and its companion spring member being hingedly connected with the plate at spaced points, one being substantially nearer to the plate pivot than the other, and the action line of force of each spring member making a relatively small acute angle with the companion contact arm member and lying normally on the side of the arm member on which its companion stationary contact stop is located, the angle between one pair of arm and spring members being less than the angle between the other pair of arm and spring members, means for moving the plate, while the pairs of contacts remain in engagement, in a direction to shift the spring lines of action to the opposite sides of the arms in order to reverse the bias by the springs upon the arms whereby the movable contacts are moved away from said contact stops, the bias by the spring making the lesser acute angle with its contact arm being reversed before reversal of the bias by the other spring, whereby one contact arm is moved before the other, the other stops for limiting said movement of the contact arms away from the first mentioned stops in order that restoration of the contact arms to normal position may be effected by reversal of movement of the plate.

5. An electric switch according to claim 4 in which the means for moving the plate includes a thermal responsive element.

6. An electric switch according to claim 4 in which the means for moving the plate includes a spring biasing the plate for movement in a direction to separate the contacts from the first mentioned contact stops, and a thermal responsive element opposed to the spring for restraining movement of the plate thereby and for moving the plate in a direction in opposition to the spring.

'7. An electric switch according to claim 4 in which each spring is a helically coiled spring connected with the plate at a point between the plate pivot and the arm connection with the plate.

8. An electric switch according to claim 4 in which the last mentioned stops are so located as to permit the arms to move into such relative positions that the -spring, which exerted the greater bias upon its arm before its reversal of bias, exerts the greater bias after reversal where by the arm which moved first upon reversal of spring bias will be restored first to original position.

9. A circuit controller comprising two toggle switches providing for rapid separation and closing of contacts; each switch having a contact arm carrying a contact movable between stops, a biasing spring for urging the arm toward one or the other of said stops, and a movable toggle fulcrum which can be shifted relative to the action lines of the spring to change the bias of the spring; a movable member common to both switches and carrying the toggle fulcrums of said switches; means for actuating the movable member; and means for adjusting at least one of the contact stops in order that, by differing the spring bias of the springs of each of the toggle switches, the switches function separately in a predetermined sequence.

10. A circuit controller comprising two toggle switches providing for rapid separation and closing of contacts; each switch having a contact arm carrying a contact movable between stops, a biasing spring for urging the arm toward one or the other of said stops, and a movable toggle fulcrum which can be shifted relative to the action lines of the spring to change the bias of the spring; a movable member common to both switches and carrying the toggle fulcrums of said switches: means for actuating the movable member, said movable member providing one of the toggle members for each switch, the other toggle member of each switch being a contact arm; and coiled springs connected with said movable member and each of the contact arms on opposite sides of the fulcrums for each of the arms.

CALVIN J. WERNER. 

